In the fast-paced society of today, convenience is an important consideration for most people. In enterprise telecommunications switches and servers, for example it is important in certain types of calls that the callers be able to reach subscribers without numerous transfers, often only to reach a voice mailbox. Such slow, laborious, and inefficient connections can lead to customer and employee dissatisfaction and decreased productivity levels within an organization.
Bridging has been employed, for example by the EC500™ product of Avaya, Inc., to provide one-number portability and one-number access to anyone in an enterprise network. As used herein, “bridging” refers to the ability of a first communication device to answer (receive) or join contacts with a different, second communication device. Bridging, as enabled by the EC500™ product, allows for a high level of accessibility by seamlessly directing a call for a cellular phone to a designated telephone number, such as an office number, or vice versa. Both phones ring simultaneously, providing a subscriber with the option of answering on the cellular phone or the office desk set. The bridging is performed by bridging a call appearance on a line set to a virtual station that, when called, initiates a call to a selected provisioned cellular telephone number. This one-number portability is independent of the cellular standard in use. The system further provides call filtering (delivering only external calls, only internal calls, all calls or no calls to the cellular phone) and office caller ID (the cellular phone, when used to call into the enterprise switch/server, adopts the subscriber's office extension number).
The bridging system, however, can have limitations. First, the system can bridge only one call appearance for each provisioned virtual station. If a subscriber has multiple call appearances on his or her communication device, only one of the call appearances is bridged out for one provisioned virtual station. To bridge all call appearances, a separate corresponding virtual station must be provisioned, with a respective extension, for each separate call appearance, which is not only unnecessarily consumptive of scarce communications and processing resources but also expensive for businesses due to the need to upgrade to a system having an appropriate number of extensions. Second, the system does not relinquish call control decisions outboard. It merely bridges call routing decisions already made to a PSTN number. Telecommunication switches and servers now have circuit-switched and packed-switched capabilities and therefore deal with a wide variety of contact types other than traditional telephone calls and, consequently, of communication devices. As a result of this diversification, current communication devices have a wide range of intelligence capabilities compared to traditional digital and analog telephones. For example, the Session Initiation Protocol or SIP provides for intelligent endpoints, having autonomy and feature richness. Under the messaging scheme, which uses an “invite” message to accept a contact followed by various other messages, such as “trying”, “ringing”, “acknowledge”, and “OK”, the endpoints can refuse to accept a contact. Third, the system is enabled currently only for cellular phones.